/*
 * Tencent is pleased to support the open source community by making BK-CI 蓝鲸持续集成平台 available.
 *
 * Copyright (C) 2019 THL A29 Limited, a Tencent company.  All rights reserved.
 *
 * BK-CI 蓝鲸持续集成平台 is licensed under the MIT license.
 *
 * A copy of the MIT License is included in this file.
 *
 *
 * Terms of the MIT License:
 * ---------------------------------------------------
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
 * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of
 * the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
 * LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
 * NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package com.tencent.bkrepo.common.storage.core.overlay

import com.tencent.bkrepo.common.storage.pojo.RegionResource
import java.io.InputStream

class OverlayArtifactFileInputStream(
    fileRanges: List<RegionResource>,
    val loader: (RegionResource) -> InputStream
) : InputStream() {

    private val it = fileRanges.iterator()
    private var delegate: InputStream = next()

    override fun read(): Int {
        val read = delegate.read()
        if (read == -1) {
            // 更新到下一条流
            if (moveToNextInputStream()) {
                return read()
            }
        }
        return read
    }

    override fun read(b: ByteArray, off: Int, len: Int): Int {
        val read = delegate.read(b, off, len)
        if (read == -1) {
            if (moveToNextInputStream()) {
                return read(b, off, len)
            }
        }
        return read
    }

    private fun moveToNextInputStream(): Boolean {
        if (this.hasNext()) {
            delegate = next()
            return true
        }
        return false
    }

    private fun hasNext(): Boolean {
        return it.hasNext()
    }

    private fun next(): InputStream {
        val fileRange = it.next()
        return loader(fileRange)
    }
}
